Originally Posted by CdCf

Let's say a sprint finish for Robbie McEwen requires him to put out 500 W. His gear is 53/11 and he's riding on 20 mm tyres. Let's also assume that the sprint is at 60 km/h. 60 km/h is 16.7 m/s, and the circumference of a wheel is 2.074 m. That means ~8 wheel revolutions per second, and the 4.82 pedal-to-wheel ratio gives us a cadence of ~100, or 1.7 revs/sec. Dividing power by "second-cadence" gives torque, and 500 W / 1.7 r/s = 294 Nm. That's his average torque. Peak torque per half pedal cycle will be higher. How much higher is hard to say.